Delayed switchboard lamp system



March 16, 1954 1 o. YEOMANS DELAYED swITcHBoARD LAMP SYSTEM Filed Nov. 28, 1951 WEA/ro@ BV .O. VEO/VANS jkm ATTO/MEV Patented Mar. 16, 1954 DEEAYEDSWITCHBOARD SYSTEM' Luci-en Osborn i-Yeom'ans, Merrick; h N.- Y'., fassigno'r tof American.:V Telephone and Telegraph Companm-.afoorporationof New York pplicationNofvemei 28, 1951', Serial No.' 258,604

7 claims; (ci. msg-5s.)

This invention relate'sff to; electrical signaling and more particularly-'to signaling? syste'rnsf 'em'- pl'ying lamps* or other devices`Y fori producing multiple signals;

- i vThe objects of the inventiona're' tol secure' im'- p'rov'ed operationin electrical signaling; tolefect the successive lighting of' multiple answering la'ni'ps' at manual telephone switehbo'ardsl; and" in general t improve thi-:construction ofslgil'alihg devices'so as to increase theeicie'ncy of-th'e systems in" which they aref einplc'iy'ecl.`

' itl'ie' past ithas been the practice' iii-'manual telephone s'rsteni's` to provide simultaneous' lamp appearances'in multiple switchboards for each 'subscribers circuit. Duringthe periodswhen the traino' on such switehboards is weil. within the capa-city of the operators, there occur-s'- what is known as* fighting for lights-L For every" call answered by an operator, severalother'operator's makea start toward:` answering the same call. The Wasted motion and nervous strain ofi these false 'starts tenusto fatigue the operatorsanu `decreases`` their efficiency'.

According tovv the present invention improvements are obtained in' signalingsystems off' the above-mentioned character by successively delia'yiiig" nio lighting ofthe signoilampsossooiateo with a subs'cribers` line thereby eliminating the `simiiltarieous lighting: of the lamps' of a parallel "group and 'the consequent fighting for' lights by the' operators.

l feature ofthisinventionresides iti-*equipping the iarnentoir'cuits of the sign'ailamp's withia resistor, such as boron, silver-sulphide; or' other naterioirh'avingia high negative temperature 'co1 iciehtiof resistance; the resi'Stor'"being mounted in seri-es" with the'J lameht, sothat the iigliting `oithe lamp' is'delayed until'the reslst'iifheat's sufficiently to lowerfits lresistal1-fleeand allowsvadee quate currittop's's'toilight-'the lamp. Successive lighting of parallel appearance lamps is thehiobtiied by varying the size', shape; orstructure of the resistor at the findividuai` lamps or even omitting it at one lamp of a multiple group. With thisarrangement, it possible to select resistors with va ingheatiifg'iintervals so that each successive' lamp 'will li'gltafter a predetermined interval.

The foregoing and other features of this invention will be described more fully in detail in the following specication.

Referring to the drawing, each of the subscribers lines such as the line Ll appears in the central office lin a suitable connecting device. The line LI is shown terminating in answering jacks' I0; 2U and 30,*and is providedwithwanindividual line relay 4f and cut-olf relay 5.1 In addition the line LAIT i"s provided# with` individual liielamps H; 2land`31mou'nted inlany'fsuitable position before the operators. The operators positions-are equippedv Wlithf the usual cordl cirv cuit suchaslcord' 46.

Ther-line' lamps lll, 2|; 3l comprise -a glass bulb, a luminousvflament, a resistor, and' exterior ter-` minals. The filamentA is'se'aled Within the glass bulba'n'd is connectedin series with the resistor. Thisre'sistor may beeither'insicle' orfoutsid the bulb lbut the preferable posit-ion'is inside the -bulb A brief descriptionWillt now beg'iven ofv the n'ianner-I in `which the system; of? the drawingA oper'- `aises: When the subscriber offline'Ll lrerr'io'veshis telephone receiver from-the vho'okf to initiate a call, a4 circuit' isclosed through tlieline'r'elay `lo'f the calling subscribers line circuit LGI. This relay operates andicloses acircuit from ground through its armatar-ev and contact, throughl the contact and armature 3 of' the' cut-#oliil relay 51, the lamerit'l lf2`l` of the'line lamp H tofbattery, andthe line lamp'- H lights to attracty the att'el'itiorli of the operator at position M. The line' lamps 2`| and"3 l 'do not lightimmedately si-'nc'e the Iresistors 233i and '3"3`fh`aveV not-had time 'to heatV and*y the 'resistance is high solas to prevent-the passage o'fl sufficient current to Alight the lamps 2-1 and' 311 Assuming that the' operator atpositfion M' is available; she answers the call by inserting the plug j of the cordlinthe' jackf'of the cal-ling line The insertion of "the` plug? in the jack completes a circuitf'rom batteryv through the sleeveofj" the plug"` 4E? and"y jack 30, through tlieline y-G and the Winding ofv the cauti-olii relay 5j to gro'ur'id. The cute-oil"-4 relayl 5` operates and disconnects the line relayllif-rom' the suhscriio'ertsl line; The line re'- lay 4 releases and` extinguishes the filaments-of all'the line lamps:

'ii-hel operator completestie' connection by inyser-tingth'e plug 47 into-the jack fof'th'elca'lled subscribers1inecireuit E612.k establishes va circuit from battery througlii the sleeve or the plug 41- almeria/ck '50; throughthe' out-orti relay 55 tol-ground. 'Iiiecutboi relay operates `and4` diseonneots the line-relay sa vfroinriV the -oaiia sub1'- scribers line L2 so that any associated line lamps Il line relays to the subscribers circuit.

If the operator at position M does not answer the call Within a reasonable interval, for example one second, the current through the resistor 23 will cause its temperature to rise and as the temperature rises the resistance drops. When the resistance has dropped suiiciently the increased current will light the lamp 2l thereby attracting the attention of the operator at position N. If the call remains unanswered at the end of the second interval, the line lamp 3l at operator position O, with the two-second delay will then light.

This procedure will continue until an available operator answers the call by inserting the plug of her cord circuit into an answering jack of the calling line in the manner described.

What is claimed is:

1. In a signaling system, the combination comprising a plurality of signaling devices, a plurality of resistors having a negative temperature coefficient of resistance each individually connected in series with a different one of said signaling devices, each of said resistors undergoing a different change in its current carrying characteristics when heated by current and being effective to delay the operation of said signaling devices, electrical circuits including said signaling devices and said resistors, and means for energizing said circuits whereby the operation of each of said signaling devices in succession is effected.

2. The combination in a signaling system of a plurality of signal lamps, a plurality of resistors having a negative temperature coeiiicient of resistance, each individually connected in series with a different one of said lamps, each of said resistors undergoing a diierent change in its electrical characteristics when heated by electric current and being effective to delay the illumination of the series connected lamp, electrical circuits including said lamps and resistors, and means for energizing said circuits in response to a signaling condition whereby the lighting of each of said lamps in succession is eiected.

3. The combination in a signaling system of a plurality of lamps, said lamps comprising a plurality of glass bulbs, a plurality of filaments each within a diierent one of said glass bulbs, a plurality of resistance elements having a negative temperature coeilcient of resistance each mounted within a diierent one of said bulbs and electrically connected in series with the said iilaments, each of said resistance elements undergoing diierent changes in its electrical characteristics when heated by electric current and being effective to delay the illumination of the series connected filament, electrical circuits in- .f

cluding the said lament and said resistance elements, and means operatively responsive to a signaling condition for supplying current to said circuits whereby the lighting of each of said lamps in succession is effected.

4. In a multiposition switchboard of a tele` phone system, a line, a plurality of answering lamps for said line, one lamp at each position, means individual to said line and operatively responsive to a calling condition for energizing the plurality of lamps individual thereto, and a plurality of resistance elements having a negative temperature coeilicient of resistance each individually connected in series with a diicrent one of said lamps, each of said resistance elements differing in its heating interval and being effective to delay the illumination of the lamp to which it is individual whereby the lighting of each of said lamps in succession is effected.

5. In a multiposition switchboard of a telephone system, a line, a plurality of multiple answering jacks and lamps for said line, one jack and lamp at each position, means individual to said line and operatively responsible to a calling condition for energizing the plurality of lamps individual thereto, a plurality of resistance elements having a negative temperature coefficient of resistance each individually connected in series with a different one of said lamps, each of said resistance elements differing in its heating interval and being effective to delay the illumination of the series connected lamp, whereby the lighting of each of said lamps in succession is effected, and means at each switchboard position for answering incoming calls.

6. In a multiposition switchboard of a telephone system, a line, a plurality of multiple answering lamps for said line, one lamp for each position, said lamps comprising a plurality of glass bulbs, a plurality of. laments, each within a diierent one of said bulbs, and a plurality of resistance elements having a negative coefcient of resistance each mounted within a different one of said bulbs and connected in series with the said filaments, each of said resistance elements differing in its heating interval and being efiective to delay the illumination of the series connected, filament, means individual to said line and operatively responsive to a calling condition for energizing the plurality of lamps individual thereto whereby the lighting of each of said lamps in succession is eiected.

7. In a multiposition switchboard of a telephone system, a line, a plurality of multiple answering jacks and lamps for saidline, one jack and lamp for each position, said lamps comprising a plurality of glass bulbs, a plurality or" laments each within a different one of said bulbs, and a plurality of resistance elements having a negative temperature coeilicient of resistance, each mounted within a different one oi said bulbs and connected in series with the said filaments, each of said resistance elements differing in its heating interval and being effective to delay the illumination of the series connected filament, means individual to said line and operatively responsive to a calling condition for energizing the plurality of lamps individual thereto whereby the lighting of each of said lamps in succession is eiected, and means at each switchboard position for answering incoming calls manifested by the lighting of its position lamps.

LCIEN OSBORN YEOMANS.

References Cited' in the le of this patent Y UNITED STATES PATENTS Number Name Date 1,217,715 Crane Feb. 27, 1917 1,637,403 Abbott Aug. 2, 1927 2,566,426 Parks Sept. 9, 1951 

